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At least 793 records · Page 44Linked to original sources
PubMed2004

Evaluation of cartilage repair tissue after biomaterial implantation in rat patella by using T2 mapping.

To evaluate the ability of MR T2 mapping (8.5 T) to characterize ex vivo longitudinally, morphologically and quantitatively, alginate-based tissue engineering in a rat model of patellar cartilage chondral focal defect. Calibrated rat patellar cartilage defects (1.3 mm) were created at day 0 (D0) and alginate sponge with (Sp/C+) or without (Sp/C-) autologous chondrocytes were implanted. Animals were sacrificed sequentially at D20, D40 and D60 after surgery and dissected patellae underwent MRI exploration (8.5 T). T2 values were calculated from eight SE images by using nonlinear least-squares curve fitting on a pixel-by-pixel basis (constant repetition time of 1.5 s, eight different echo times: 5.5, 7.5, 10.5, 12.5, 15.0, 20.0, 25.0 and 30.0 ms). On the T2 map, acquired in a transversal plane through the repair zone, global T2 values and zonal variation of T2 values of repair tissue were evaluated versus control group and compared with macroscopic score and histological studies (toluidine blue, sirius red and hematoxylin-eosin). "Partial", "total" and "hypertrophic" repair patterns were identified. At D40 and D60, Sp/C+ group was characterized by a higher proportion of "total" repair in comparison to Sp/C- group. At D60, the proportion of "hypertrophic" repair was two fold in Sp/C- group versus Sp/C+ group. As confirmed morphologically and histologically, the T2 map also permitted the distinction of three types of repair tissue: "total", "partial" and "hypertrophic". "Total" repair tissue was characterized by high T2 values versus normal cartilage (p<0.05). Zonal variation, reflecting the collagen network organization, appeared only at D60 for Sp/C+ group (p<0.05). "Hypertrophic" tissue, mainly observed at D60, presented high T2 global values without zonal variation with cartilage depth. These results confirm the potency of the MR T2 map (8.5 T) to characterize macroscopically and microscopically the patterns of the scaffold guided-tissue repair of a focal chondral lesion in the rat patella ("total", "partial" and "hypertrophic"). On T2 map, three parameters (i.e. MRI macroscopic pattern, T2 global values and zonal variation of T2 values) permit to characterize chondral repair tissue, as a virtual biopsy.

Animals↗
PubMed2006

Study of metals concentration levels in Patella piperata throughout the Canary Islands, Spain.

In order to assess the extent of metal contamination at rocky shores of the Canarian Archipelago, metal concentrations have been measured in Patella piperata (Gould, 1846), using the standard atomic absorption spectrophotometer technique. Ranges of elements concentrations measured (in microg g(-1)) found in the biota were: Cd (0.36 +/- 0.26 microg g(-1) dry wt.), Cu (2.05 +/- 0.91 dry wt.), Pb (1.57 +/- 1.14 microg g(-1)dry wt.) and Zn (10.37 +/- 4.60 microg g(-1) dry wt.). Variation in metal concentrations in Patella, was tested by using non-parametric statistical methods. Cd content had a maximum in the Archipelago Chinijo, northward of Lanzarote Island. The metal concentrations recorded at the clean stations may be considered carefully if they are used like background levels.

Animals↗
PubMed1990

Changes in junctional communication associated with cell cycle arrest and differentiation of trochoblasts in embryos of Patella vulgata.

In early embryos of molluscs, different clones of successively determined trochoblasts differentiate into prototroch cells and together contribute to the formation of a ciliated ring of cells known as the prototroch. Trochoblasts differentiate after cell cycle arrest, which occurs two cell cycles after the commitment of their stem cell. To study the changes of junctional communication in embryos of Patella vulgata in relation to commitment, cell cycle arrest, and differentiation of the trochoblasts, we have monitored electrical coupling as well as transfer of fluorescent dyes. The appearance of dye coupling in embryos of Patella occurs after the fifth cleavage (at the 32-cell stage), when the cell cycles of all embryonic cells become asynchronous and longer. At the 32- and 64-cell stages all cells are well coupled. However, after the 72-cell stage dye transfer to or from any cell of the four interradial clones of four primary trochoblasts becomes abruptly reduced, whereas electrical coupling between these cells and the rest of the embryo can still be detected. From scanning electron microscopical analysis of the cell pattern we conclude that this change in gap junctional communication coincides with cell cycle arrest and with the development of cilia in all four clones of primary trochoblasts. Similarly, after the 88-cell stage the four radial clones of accessory trochoblasts stop dividing, reduce cell coupling, and become ciliated. By the formation of the prototroch, the embryo becomes subdivided into an anterior (pretrochal) and a posterior (posttrochal) domain which will develop different structures of the adult. At the 88-cell stage, the cells within each of these two domains remain well coupled and form two different communication compartments that are separated from each other by the interposed ring of uncoupled trochoblasts. The relations among control of cell cycle, changes in junctional communication, and differentiation are discussed.

Animals↗
PubMed1992

Activation of polyphosphoinositide metabolism at artificial maturation of Patella vulgata oocytes.

The metabolism of polyphosphoinositides (PPI) has been investigated during the meiosis reinitiation of the oocytes of a prosobranch mollusk, the limpet Patella vulgata. Meiosis reinitiation which leads to germinal vesicle breakdown (GVBD) and metaphase-1 spindle formation was artificially induced by treating the prophase-blocked oocytes with 10 mM NH4Cl, pH 8.2. This treatment, which results in a rise in intracellular pH, triggered a general increase in polyphosphoinositide synthesis. Determinations of phosphorus content showed that maturation induced a 30 to 50% increase in both phosphatidylinositol (PI) and phosphatidylinositol-1 monophosphate (PIP) concentrations. Incorporations of 32PO4 and [3H]inositol have been measured in three classes of polyphosphoinositides: PI, PIP, and phosphatidylinositol 4,5-bisphosphate (PIP2). By comparing incorporation rates of the radiolabeled precursors into PPI before and after meiosis reinitiation, we found that artificial maturation by ammonia induced a 50-fold increase in the turnover of these lipids. No significant burst of inositol 1,4,5-trisphosphate (IP3) was observed after maturation. We suggest that modifications in PPI metabolism occurring at maturation of Patella oocytes might ensure the formation of an important stock of PPI that would be available for the profuse production of IP3, the messenger responsible for the Ca2+ signal at fertilization.

Ammonia↗
PubMed1988

Inhibition of dye-coupling in Patella (Mollusca) embryos by microinjection of antiserum against nephrops (Arthropoda) gap junctions.

Antiserum raised against Nephrops gap junctions was injected into single cells of the 2-, 4-, 8-, 16-, and 32-cell stage of the Patella vulgata embryos. The pattern of junctional communication by iontophoresis of Lucifer Yellow CH was tested at the 32-cell stage. The results show that the normal pattern of dye-coupling at the 32-cell stage is disrupted in greater than 65% of embryos previously injected with antisera. In contrast, less than 15% of embryos injected with preimmune serum exhibited disrupted patterns of dye-coupling. Up to the late 32-cell stage no effect of the antiserum on the pattern of cleavage was detected. This antiserum may provide a powerful tool to investigate the role of junctional communication in later stages of development of Patella embryos.

Animals↗
PubMed2002

Endoscopic anterior cruciate ligament reconstruction with patella tendon autograft.

The patella tendon is the most commonly used graft source for ACL reconstruction because of its biomechanical strength and stiffness, the availability of bone-to-bone healing on either end, and the ability to firmly secure the graft within the tunnels. Consistently good results have been reported in the literature, with expectations to return to all activities at pre-injury levels of performance. We outline our technique for endoscopic ACL reconstruction using a patella tendon autograft. The technique is divided into the critical stages of pre-operative assessment, graft harvest, notch preparation, tunnel placement, graft passage, graft fixation, and rehabilitation. Methods for avoiding pitfalls and overcoming mishaps are described.

Anterior Cruciate Ligament Injuries↗
PubMed2003

Metallothionein concentrations in a population of Patella aspera: variation with size.

The determination of metallothionein (MT) concentrations in species with different feeding habits is important from the ecotoxicological point of view because it provides a better understanding of the role of these proteins in metal uptake pathways. The main objective was study the variation of MT and metal (Cd, Cu and Zn) concentrations with size and weight in the limpets Patella aspera. In addition investigate the relationship between MT and metal concentrations in limpets from different metal load environments of the south coast of Portugal with the aim to use MT in P. aspera as a biomarker of metal exposure. MT concentrations in the whole soft tissues of P. aspera increased with size and weight while metals decrease with size and weight. MT concentrations showed no significant relationship with Cd or Cu concentrations in the limpets from the South Portuguese Coast. However, a negative exponential relationship detected between MT and Zn concentrations suggest that Zn bound to MT might be displaced by Cd or Cu ions. The ability of limpets to store both Cd and Cu bound to MT may be responsible for the tolerance of this species to contaminated environments. The relationship between MT concentrations and Zn indicates that MT seems to play a minor role in binding Zn in Patella species.

Adaptation, Physiological↗
PubMed1997

Cell-lineage and clonal-contribution map of the trochophore larva of Patella vulgata (mollusca).

Molluscan development is characterised by its extremely regular cleavage pattern. In numerous molluscs the fate of various early-cleavage stage blastomeres has been determined and fate maps have been constructed. On the basis of similarities between these fate maps, a generalised molluscan cell-lineage map has been constructed. Recently, the validity of this map has been challenged. In this study, the cell-lineage of the first-, second-, and third-quartet micromeres and third-generation macromeres of the equally-cleaving gastropod mollusc Patella vulgata was studied by fluorescent cell-lineage tracer injection followed by epifluorescence microscopy and confocal laser scanning microscopy. For the first time, a complete cell-lineage map, in the form of a clonal-contribution map of the trochophore, has been constructed with the use of fluorescent cell-lineage tracers. This map both agrees and differs in a number of respects with the generalised cell-lineage map of molluscs. The most important deviation is that the micromere 2d, formerly referred to as the first somatoblast, is not the only cell that forms the foot and shell gland in Patella.

Animals↗
PubMed2000

Recurrent non-Hodgkin's lymphoma presenting as pathological fracture of the patella.

We report a case of recurrent non-Hodgkin's lymphoma presenting as anterior knee pain due to pathological fracture of the patella. Anterior knee pains is an extremely common presenting complaint at orthopaedic clinics and the patella is an infrequent site both for primary and recurrent tumours. This case, treated by patellectomy, illustrates the difficulty of treatment of these lesions and highlights the importance of adequate radiological assessment in sites of previous tumour involvement.

Journal Article↗
PubMed2004

Congenital and irreducible non-traumatic dislocation of the patella--a modified soft tissue procedure.

Many procedures have been described for the correction of congenital dislocation of the patella. Most operations entail extensive soft tissue releases through curved skin incisions. A modification of the Langenskiold and Ritsila procedure is described. The main alterations include a limited and straight anterior skin incision, a fashioning of a 'buckle' of the transferred distal-patellar tendon to a distally based flap and the transposition of an extensive medial rotation flap. This report describes the early results (mean=19 months) of the modified procedure in three cases of congenital lateral dislocation of the patella.

Child↗
PubMed2003

Spatial and temporal variation of the fatty acid composition of Patella spp. (Gastropoda: Prosobranchia) soft bodies and gonads.

This study evaluated the effects of season and spatial distribution on the fatty acid composition of Patella depressa gonads and Patella spp. soft body tissue. The results show that the quantitatively most important fatty acids were the saturated fatty acids (SFA) 16:0, 14:0 and 18:0; the monounsaturated fatty acids (MUFA) 18:1(n-7), 18:1(n-9), 16:1(n-7) and 20:1(n-9) and the polyunsaturated fatty acids (PUFA) eicosapentaenoic acid (EPA 20:5(n-3)), and arachidonic acid (ARA 20:4(n-6)). P. depressa and P. ulyssiponensis soft body fatty acid profiles revealed significant differences between sexes; males showed significantly higher percentages of PUFA, highly unsaturated fatty acids (HUFA), (n-3) fatty acids and ARA, while in females significantly higher proportions of MUFA were found. Analysis of variance on the fatty acid composition of P. depressa gonads revealed significant differences between sexes, which were more marked than when the whole body was analysed. Males showed a significantly higher percentage of PUFA, HUFA, fatty acids from the (n-3) and (n-6) series, ARA and EPA, while females were seen to have higher proportions of SFA, MUFA and total fatty acid methyl esters (FAME). Some variability was seen to occur due to shore location and seasons, but these effects were not so obvious.

Analysis of Variance↗
PubMed2002

Localization studies of ioactive cyclic peptides in the ascidian Lissoclinum patella.

A Palauan specimen of the ascidian Lissoclinum patella contained the cyclic peptides patellamides A-C. In contrast to previous reports concerning the location of cyclic peptides in L. patella and L. bistratum, it has been demonstrated that these cyclic peptides were not located in the symbiotic cyanobacterium Prochloron sp. but were instead distributed throughout the ascidian tunic. The relevance of these results with respect to the biosynthetic origins of the patellamides is discussed.

Animals↗
PubMed2003

[Internal rotational strength of the thigh after ACL reconstruction. Prospective comparison of harvesting of the semitendinosus and gracilis tendons and the patella tendon].

AIM: The aim of the present study was the prospective, randomized evaluation of the internal rotation strength in patients, undergoing ACL reconstruction using either semitendinosus and gracilis tendon autografts (ST/G) or the central third of the patella tendon (BPT). METHOD: 40 patients (20 male, 20 female, average age 32 years [16 - 49]) underwent reconstruction of the ACL. In 20 patients ST/G was used, in 20 matched patients the central third of the patella tendon (BPT) was used. Rehabilitation was identical for both groups. The isometric strength of internal tibial rotation in neutral position was measured preoperatively, 3, 6 and 12 months postoperatively. RESULTS: After 3 months no difference to the preoperative data was found. After six months the internal tibial torque was significantly higher (p < 0.05) than preoperatively. No additional increase was found after 12 months. There was no statistically significant difference between both groups at any time. CONCLUSION: The internal tibial torque, which is predominantly a function of the pes anserinus, recovers shortly after operation and is, due to postoperative rehabilitation, significantly elevated after 6 months. The randomized comparison with the harvesting of the central third of the patellar tendon showed no significant difference.

Adolescent↗
PubMed2002

Changes in muscle torque following anterior cruciate ligament reconstruction: a comparison between hamstrings and patella tendon graft procedures on 45 patients.

We designed a prospective study to examine the influence of graft type (hamstring or patella tendon) on thigh muscle torque recovery after anterior cruciate ligament reconstruction. 60 patients undergoing ACL reconstruction, using a hamstring or patella tendon graft, were studied and 45 were followed up to 1 year. Concentric and eccentric quadriceps and hamstring torque were recorded, using an isokinetic dynamometer preoperatively, 6 and 12 months after ACL reconstruction. We found an improvement in all muscle functions in both the operated and unoperated legs during the recovery period. Graft type had no effect on recovery. During the first 6 months, torque was restored to preoperative levels and continued to improve in all muscles and actions between 6 months and 1 year.

Adult↗
PubMed2004

The management of superior dislocation of the patella with interlocking osteophytes--an update on a rare problem.

The superior dislocation of the patella with interlocking osteophytes is a rare condition. A review of the English literature revealed only 12 reported cases. The purpose of reviewing these case reports is to highlight the unusual presentation and the injury mechanism in 2 of our patients, and to present our treatment algorithm. Closed reduction with manipulation of the patella, with or without anaesthesia, was performed without difficulty. We recommend an intermediate step of trying a regional nerve block before proceeding to general anaesthesia. Our patients had full range-of-motion after reduction and they were symptom-free after 3 years of follow-up. There were no recurrent dislocations in our patients.

Aged↗
PubMed1994

Transcriptional regulation of tubulin gene expression in differentiating trochoblasts during early development of Patella vulgata.

The expression of alpha- and beta-tubulin genes during the early development of the marine mollusk Patella vulgata has been investigated. From the 32-cell stage onwards, an enhanced expression of both alpha- and beta-tubulin mRNAs was detected in the primary trochoblasts. After one additional cleavage, these cells become cleavage-arrested and then form cilia. They are the first cells to differentiate during Patella development. Later, alpha- and beta-tubulin mRNA is also found in the accessory and secondary trochoblasts. Together these three cell-lines form the prototroch, the ciliated locomotory organ of the trochophore larva. The early and abundant expression of tubulin genes precede and accompany cilia formation in the trochoblasts and provides us with an excellent molecular differentiation marker for these cells. Apart from the trochoblasts, tubulin gene expression was also found in other cells at some stages. At the 88-cell stage, elevated tubulin mRNA levels were found around the large nucleus of the mesodermal stem cell 4d. In later stages, tubulin gene expression was detected in the cells that form the flagella of the apical tuft and in the refractive bodies. An alpha-tubulin gene was isolated and characterized. A lacZ fusion gene under control of the 5' upstream region of this tubulin gene was microinjected into embryos at the two-cell stage. The reporter gene product was only detected in the three trochoblast cell-lines at the same time as tubulin genes were expressed in these cells. Reporter gene product was not detected in any other cells. Thus, this 5' upstream region of this alpha-tubulin gene contains all the elements required for the correct spatiotemporal pattern of expression.

Amino Acid Sequence↗
PubMed2002

Expression pattern of Brachyury in the mollusc Patella vulgata suggests a conserved role in the establishment of the AP axis in Bilateria.

We report the characterisation of a Brachyury ortholog (PvuBra) in the marine gastropod Patella vulgata. In this mollusc, the embryo displays an equal cleavage pattern until the 32-cell stage. There, an inductive event takes place that sets up the bilateral symmetry, by specifying one of the four initially equipotent vegetal macromeres as the posterior pole of all subsequent morphogenesis. This macromere, usually designated as 3D, will subsequently act as an organiser. We show that 3D expresses PvuBra as soon as its fate is determined. As reported for another mollusc (J. D. Lambert and L. M. Nagy (2001) Development 128, 45-56), we found that 3D determination and activity also involve the activation of the MAP kinase ERK, and we further show that PvuBra expression in 3D requires ERK activity. PvuBra expression then rapidly spreads to neighbouring cells that cleave in a bilateral fashion and whose progeny will constitute the posterior edge of the blastopore during gastrulation, suggesting a role for PvuBra in regulating cell movements and cleavage morphology in Patella. Until the completion of gastrulation, PvuBra expression is maintained at the posterior pole, and along the developing anterior-posterior axis. Comparing this expression pattern with what is known in other Bilateria, we advocate that Brachyury might have a conserved role in the regulation of anterior-posterior patterning among Bilateria, through the maintenance of a posterior growth zone, suggesting that a teloblastic mode of axis formation might be ancestral to the Bilateria.

Amino Acid Sequence↗
PubMed1982

The effect of anterior displacement of the tibial tuberosity in idiopathic chondromalacia patellae: a prospective randomized study.

In 42 patients with idiopathic chondromalacia patellae, the effect of anterior displacement of the tibial tuberosity was evaluated in a prospective and randomized study. The operation performed was a modified Bandi procedure, and it resulted in significant relief of the patellofemoral pains, compared with the effect of a standard shaving procedure. Shaving alone was done in 22 patients of whom 6 (27 per cent) were classified as good, a result which may have been due to the placebo effect. In another 20 patients shaving was combined with anterior displacement of the tibial tuberosity resulting in pain relief in 18 (9 degrees per cent). The lack of unambiguously good results may be due to the fact that, although an anterior displacement reduces the retropatellar pressure, it cannot by itself compensate for an abnormal, dynamic tracking pattern of the patella.

Adult↗